It wasn't the norm, that's a myth. Child birth is dangerous, having children that young was even more dangerous. Children of rich families were married off young for political reasons, but even they waited with having children until they were older.
"Und fügt es sich, daß auch Andersgläubige, Andersnationale unter uns wohnen, so werden wir ihnen einen ehrenvollen Schutz und die Rechtsgleichheit gewähren."
"And should it happen that people of other faiths and other nationalities live amongst us, we shall grant them honourable protection and equal rights."
Shit like this is completely unusable for laymen.